This invention relates to representing inks in electronic document systems. Computer programs such as page layout programs, graphical illustration programs and image processing programs provide users with the ability to create, edit and display electronic documents that can include color. Typically, such programs also provide users with the ability to print their documents, and many programs attempt to represent documents on the computer monitor in colors that bear some relation to the colors that will be output by a printer.
Printers typically use inks to print documents, which can be differentiated by the appearance or color one perceives when viewing the ink. Traditional printing systems can use inks of two types, process inks and spot inks. Process inks, which typically include the colors cyan, magenta, yellow and black (also referred to as C, M, Y and K, respectively), are used in so-called process printing to produce full-color photographs and designs. When combinations of these inks are printed as a series of halftone dot patterns, they can create the appearance of a wide variety of colors.
Spot inks, on the other hand, are inks other than the process inks, such as specially mixed inks, that are applied individually to the printed page. Spot inks are typically used to match a particular color in a document, or when only a small number of colors will be printed on the page. Typically, spot inks are specified by spot color printing systems, such as the PANTONE®, DIC, TOYO or ANPA systems. If a specific color is desired in a printed document, a spot ink can often provide the desired color more accurately than a mixture of process inks. However, spot inks tend to be more expensive than process inks, so that using more than a few spot inks in a printing process increases the cost. Accordingly, using process inks to achieve a range of desired colors is typically more economical for printing a broad spectrum of colors.